For example, a stator vane, which is one of the components of a gas turbine, is exposed to the highest temperature combustion gas in a gas turbine. Accordingly, in the stator vane, inevitably develop damages such as cracks due to thermal fatigue, as a main factor, ascribable to the thermal stress at the time of start and stop. The stator vane also suffers damages due to other factors including creep damage and fatigue damage in addition to thermal fatigue.
Conventionally, when such damages develop, the damaged portions are repaired, for example, by the TIG welding and the stator vane is continuously used. Here, due to the thermal effect exerted by welding at the time of repairing and for the purpose of removing the residual stress, a deformation is caused in the stator vane. On the other hand, as the elevation of operational temperature of a gas turbine is promoted, the repair work load has been increased. Accordingly, it comes to be not easy to eliminate or minimize the deformation occurring in the stator vane. Such a deformation occurs in other machines as well as in gas turbines.
Proposals for solving these problems have been presented in Patent Documents 1 to 3.
The proposals of Patent Documents 1 to 3 are common in that a mixture composed of a powder (base material powder) of the same materials as the base of the component to be repaired and a brazing material powder is filled in the portion where the damage has developed. For example, in Patent Document 3, as shown in FIGS. 11A to 11C, the oxide layer of the surface portion of the base 70 of a stator vane of a gas turbine, which portion suffers cracks 71 developing therein, is scraped away in such a way that the cracks 71 partially remain unremoved; in the scraped portion, an equivalent-to-base material 72 (blank circles) composed of a material equivalent to the base 70 of the stator vane and a brazing material 73 (solid black circles) lower in melting point than the equivalent-to-base material 72 are filled; then, heat treatment is conducted while pressurizing with an inert gas, and thus the brazing material 73 is melted to perform the brazing of the cracks 71 by diffusion.    Patent Document 1: Japanese Patent Laid-Open No. 11-33832    Patent Document 2: Japanese Patent Laid-Open No. 11-43706    Patent Document 3: Japanese Patent Laid-Open No. 2006-46147